Blow torches



Jan. 27, 1959 A. scHoENwALD 2,870,825

' BLOW ToRcHEs Filed July 17, 195e United States Eatent G M' Browrancune Alexander Scheenwald, Grove City, Pa., assigner to P. Wall Mfg.Qompany, Grove City, Pa., a corporation of Pennsyivania Application July17, 1956, Serial No. 2 Claims. (Cl.,15833) temporarily supplying airpast the nozzle at pressure greater than the air pressure required for anormal flow of fuel to the nozzlethe supply of air for initialvaporization of the fuel being automatically cut off when the airpressure for feeding the fuel is at normal working pressure, after theflame has been started by a match or other lighter during the supply ofhigh pressure air for vaporization.

Another object of my invention is to provide means in a blow torch forpreheating the supply of fuel during its ow to the burner nozzle.

The single figure of the accompanying drawing is a cross sectional viewthrough a blow torch that embodies my inventive features.

The numeral 2 represents a fuel tank of conventional form having allling cap 3, an air inlet 4 from a suitable source of air underpressure, and a pipe 5 through which fuel is discharged by air pressureentrapped in the upper portion of the tank 2.

My invention includes a burner body 7 having an improved arrangement ofpassageways and control devices whereby the foregoing objects areobtained. The body has suitably secured thereto a burner tube 8 that isprovided with a suitable number of openings 9 through which will bedrawn air for combustion in the tube during normal operation of thetorch. The valve block or body has a passageway 10 therein whichcommunicates past a valve 11 with a passageway 12 that, in turn,communicates with the space between an air-mixing nozzle 13 which isconcentric with a fuel nozzle 14 that is controlled by the usual fuelvalve and its stem 15.

When air under perhaps p. s. i. is supplied into the tank and throughthe passages 10 and 12 to the air-mixing nozzle 13, fuel also is beingsupplied into the nozzle 14 at that time, from the feed pipe 5, througha coil 16 and a line 17 into the nozzle 14. The fuel will be atomizedand vaporized bythe high-pressure air, to permit of it being ignited atthe nozzle 13 as by a dame or an electrical ignition coil insertedthrough one of the openings 9.

The valve 15 will then be adjusted to a desired working position, andthe supply or air through the line 10 will be cut ot as hereinafterexplained.

Patented dan. 27, 1.959

ICC

Since air pressure considerably higher than working pressure is requiredfor effecting atomization to a point at which the ignition can besecured without preheating or priming, I use the valve 11 forautomatically cutting off the flow of air through the passageways 10 and12 when pressure in the line i is reduced to a degree suitable fornormal operation. This pressure may be in the neighborhood of 15 lbs.per square inch or some other pressure lower than the atomizing pressureabove mentioned.

The valve 11 is held to its seat by a coil spring 19, the expansiveforce of which is adjusted by a knob 20 that has screw-threadedengagement with the wall of the burner body 7. As indicated above, thestarting pressure will be perhaps 25 lbs. p. s. i., which will besuflicient to push the valve 11 from its seat and allow flow of air tothe air-mixing nozzle. When ignition has been effected, the pressure ofair in the line 4 will be reduced to a point at which the valve 11 willbe closed by its spring, but the pressure will be sufficient to securethe desired rate of fuel flow, fro-rn the discharge tube 5, for mixingwith air in the burner tube 8. The fuel passes through the coil 16 whereit is preheated and therefore will produce greater combustion efliciencyin the burner tube.

1 claim as my invention:

1. A blow torch apparatus that comprises in combination with a fuel tankwhich has means for directing air into it under pressure and has adischarge pipe therein leading upwardly from the bottom thereof, of aburner body, a forwardly-extending burner tube carried thereby andhaving air inlet openings intermediate its ends, a fuel nozzle having apassageway, that extends into the rear end of the tube, a heating coilin the tube and cornmunicating at one end with the said pipe and at itsother end with said passageway, a valve that controls fuel flow from thepassageway, a second passageway that conducts air from the upper end ofthe fuel tank to the fuel nozzle through a third passageway that isconcentric to the firstnamed passageway, and a pressure-actuated valvein the second-named passageway that is opened by the air pressure in theupper part of the tank when such pressure eX- ceeds a predetermineddegree, and is automatically closed and shuts off air flow through thissecond passageway, when the pressure falls below said degree, dischargeof air from the third-named passageway and the fuel from the rst-narnedpassageway being in the same general directlon.

2. Torch apparatus as recited in claim 1, wherein discharge from thelast-named passageways is` into an air mixing nozzle which is open intothe burner tube, at its forward side.

References Cited in the tile of this patent UNITED STATES PATENTS835,627 Loring Nov. 13, 1906 1,216,115 Hauck Feb. 13, 1917 1,914,133Kerr June 13, 1933 2,097,771 Nelson Nov. 2, 1937 2,621,718 Krautter etal Dec. 16, 1952 FOREIGN PATENTS 467,751 France Apr. 4, 1914 225,379Germany June 4, 1909

